The present invention relates to a device and method for delivering a medicament within the vagina of a patient. More particularly, the present invention relates to an intravaginal device for delivery of a medicament to the patient, the intravaginal device having a central reservoir for containing the medicament, the walls of the reservoir being comprised of a material having varying porosity depending upon whether it is desired to deliver the medicament to the vagina, prevent the delivery of the medicament, or absorb the medicament if it is desired to, for instance, limit the time or control the location to which the medicament is delivered in the vagina.
Many monolithic systems and devices for delivery of a medicament are known in the art, as are monolithic devices for delivery of the medicament or other beneficial agent in the vagina. For instance, the following U.S. Pat. Nos. disclose various devices designed to be placed in the vagina for dispensing a spermicide at a controlled, spermicidally effective release rate:
______________________________________ 2,020,107 Cruickshank 11/05/35 4,198,965 Strickman, et al. 04/22/80 4,219,016 Drobish, et al. 08/26/80 4,369,773 Chvapil 01/25/83 4,526,578 Wong 07/02/85 4,589,880 Dunn, et al. 05/20/86 ______________________________________
Also known are several U.S. Pat. Nos. describing intravaginal devices for dispensing drugs or hormones. These patents include:
______________________________________ 3,545,439 Duncan 12/08/70 3,995,633 Gougeon 12/07/76 4,286,587 Wong 09/01/81 4,312,347 Magoon, et al. 01/26/82 4,629,449 Wong 12/16/86 ______________________________________
These patents all describe devices which comprise a reservoir formed by a polymeric material which is permeable to the drug or hormone contained within the reservoir, the device itself being shaped to be retained within the vagina. U.S. Pat. No. 3,975,350, assigned to Princeton Polymer Laboratories, Incorporated is directed to the polymeric material itself.
Many U.S. Pat. Nos. describe devices comprised of polymeric materials for ingestion or placement in a body cavity, and a sample of such patents includes the following:
______________________________________ 3,946,734 Dedrick, et al. 03/30/76 4,203,440 Theeuwes 05/20/80 4,235,236 Theeuwes 11/25/80 4,309,996 Theeuwes 01/12/82 4,455,144 Michaels 01/19/84 4,578,075 Urquhart, et al. 03/25/86 4,627,851 Wong, et al. 12/09/86 ______________________________________
This last group of U.S. Pat. Nos. is listed here not because they are representative of references describing such devices but because the devices they describe are all more or less tubular in shape and include a central reservoir, the walls of the reservoir being comprised of the polymeric material. As will be seen, two of the structural features of the apparatus of the present invention can be characterized in this same manner.
The Theeuwes '440 patent is of particular interest because that patent describes a tubular device which includes a reservoir, or chambers, for containing a supply of a drug, hormone, or other beneficial agent which is dispensed from one end of the device. The drug is said to be dispensed under the influence of a pressure generating member which swells when the device is placed in a fluid environment to apply pressure against the chamber, thereby decreasing the volume of the chamber to dispense the drug. The chamber is said to be formed of an elastomeric, low modulus material which collapses in response to applied pressure.
In spite of these numerous prior patents, representing several attempts to solve the problem of efficacious delivery of a medicament to a patient, and specifically, to the vagina of the patient, there are still applications in which there is a need for an improved intravaginal device for delivery of a medicament, and a method of delivering a medicament, to a patient. For instance, even though devices such as those described in the above-listed patents are known, the prescriptions for almost all medicaments prescribed for intravaginal administration by the patient recite that the medicament should be taken before bed. The reason for that recitation is that the patient is supine when sleeping; consequently, the medicament is less likely to flow out of the vagina under the influence of gravity because the patient is not erect. A device which is capable of effectively delivering a medicament to the patient regardless of whether the patient is supine or erect not only eliminates the requirement that the medicament be administered before bed, but also makes possible the administration of the medicament around the clock. It is, therefore, an object of the present invention to provide such a device and such a method.
Another example of the need for an improved method and device for delivering a medicament in the vagina is provided by reference to the generally accepted methods for treatment of a patient with caustic medicaments such as 5-fluorouracil (5-FU). This commonly used anti-neoplastic agent, and other topically-applied medicaments, can damage the skin upon prolonged contact. Consequently, when indicated for vaginal neoplasia, 5-FU is administered by the physician, either as a cream or in propylene glycol solution, while the patient is supine so as to prevent the leaching of 5-FU out of the vagina onto the skin of the vulvular region. A device which prevents the leaching of such caustic medicaments out of the vagina would eliminate the requirement of an office or clinical visit by the patient, eliminate the possibility of damage to the skin, and make it possible to administer the medicament continuously, if desired, rather than only during the office or clinical visit, thereby increasing the efficacy of the medicament. It is, therefore, another object of the present invention to provide such a method and such a device.
It is another object of the present invention to provide a method and device capable of delivering a medicament to the vagina at a relatively constant, therapeutically effective dosage level.
Another object of the present invention is to provide a method and device for retaining a medicament within the vagina once the medicament has been delivered to the vagina.
It is another object of the present invention to provide a device having a reservoir therein for containing a sufficient quantity of a medicament to be delivered therefrom so as not to require frequent removal of the device for replenishment of the medicament.
It is another object of the present invention to provide a device and a method for topical application of a medicament to the vaginal mucosa.
These and other objects of the present invention will be apparent to those skilled in the art from the following description of a preferred embodiment thereof